Spring cushion construction and method of forming same

ABSTRACT

A spring cushion construction comprising a foamed pad having a generally flat inner surface with a depending peripheral edge, the flat inner surface including a dense outer crust. A spring assembly is disposed so that the terminal face portions thereof contact the outer crust and with the depending edge of the pad confiningly receiving the spring assembly to prevent lateral displacement therebetween. The pad is formed by a method which includes foaming a foamable material in an open top mold while leveling the upper surface of the foamable material in a manner which does not interfere with the formation of a dense outer crust thereon. The depending foam edge may then be formed by adding additional foamable material along the periphery of the pad, or by suitably attaching a preformed foam strip therealong.

United States Patent Bulloch, Jr.

SPRING CUSHION CONSTRUCTION AND METHOD OF FORMING SAME Carl GordonBulloch, Jr., 31 Kingwood Pl., Asheville, NC. 28804 Filed: June 12, 1974Appl. No.: 478,618

Related U.S. Application Data Continuation-impart of Ser. No. 298,953,Oct. 19, 1972, Pat. No 3,818,560, which is a division of Ser. No.130,328, April 1, 1971, Pat. No. 3,719,963.

Inventor:

U.S. Cl 5/354; 5/345 R, 5/351, 264/45; 297/452; 297/D1G. 2

Int. Cl. A47C 23/00; A47C 27/22 Field of Search 297/462, DIG. 1, DIG. 2;5/345 R, 351, 353, 354; 264/45 References Cited UNlTED STATES PATENTSFruchte 5/351 Ambrose 5/354 Primary Examiner-Casmir A. Nunberg Attorney,Agent, or Firm-Parrott, Bell, Seltzer. Park & Gibson [57] ABSTRACT Aspring cushion construction comprising a foamed pad having a generallyflat inner surface with a depending peripheral edge. the flat innersurface including a dense outer crust. A spring assembly is disposed sothat the terminal face portions thereof contact the outer crust and withthe depending edge of the pad confiningly receiving the spring assemblyto prevent lateral displacement therebetween. The pad is formed by amethod which includes foaming a foamable mate rial in an open top moldwhile leveling the upper sur' face of the foamable material in a mannerwhich does not interfere with the formation of a dense outer crustthereon. The depending foam edge may then be formed by adding additionalfoamablc material along the periphery of the pad, or by suitablyattaching a preformed foam strip therealong.

15 Claims. 29 Drawing Figures US Patent Sept. 23,1975 Sheet 2 of53,906,560

SOURCE SUQPLY sOUBCE- US Patent Sept. 23,1975 Sheet 3 of5 3,906,560

US Patent Sept. 23,1975 Sheet4 0f5 3,906,560

US Patent Sept. 23,1975 Sheet 5 of5 3,906,560

SPRING CUSHION CONSTRUCTION AND METHOD OF FORMING SAME The presentapplication is a continuation-in-part of pending application Ser. No.298.953. filed Oct. 19. 1972, now US. Pat. No. 3,818,560 and which inturn is a division of application Ser. No. 130.328. filed Apr. 1, 1971and now US. Pat. No. 3,719,963.

The present invention relates to a spring cushion construction for useas a seat. mattress, or the like and which comprises an outer foam padand an underlying spring assembly.

Conventionally, seat cushions of the described type are fabricated bymechanically attaching a preformed pad to an underlying spring assembly.In an attempt to prevent the springs from gradually cutting their waythrough the foam during use and thereby destroying the cushion. it iscommon to also place a fabric insulator between the springs and foam.The use of such an insulator is not altogether satisfactory. however.since it adds to the cost of the resulting product. and the relativemovement between the foam and terminal portions of the spring assemblyduring use tends to break down the insulator. thereby permitting thespring assembly to enter and cut through the foam.

It has also been proposed to fabricate foam cushions by employing afoamable elastomeric material which is adapted to form a dense outercrust along the upper surface when foamed in an open top mold. andwherein the foam rises within the mold during the foaming process toembed the terminal portions of a spring assembly being held above themold such that the crust serves to lock the springs in the foam. notefor example the patents to Koenigsberg. US. Pat. No. Re. 24.9[4 andBrown et al.. U.S. Pat. No. 3,005.2]3. However, such method results inthe foam pad and spring assembly being initially interconnected. and itis often desirable to separately fabricate the foam cushion andsubsequently interconnect the spring assembly to reduce shipping andhandling costs. Also. this latter practice has not heretofore beenfeasible when the pad is formed in an open top mold since the uppersurface which includes the dense upper crust tends to become somewhatrounded or crowned. This characteristic is particularly pronounced whena relatively large pad such as would be used in a mattress isfabricated. and the existance of the crowned surface effectivelyprecludes the subsequent positioning of a spring assembly against theupper surface since the pad would not lie flat on the spring assemblyand the central portion of the pad would be of greater thickness thanthe peripheral portions.

It is accordingly an object of the present invention to provide a springcushion construction of the described type which eliminates the need fora conventional insulater.

It is another object of the present invention to provide a foam pad foruse in a spring cushion construction and wherein the pad has a generallyflat outer surface including a dense outer crust capable of preventingpenetration by an adjacent spring assembly during prolonged use.

It is another object of the present invention to provide a foam padhaving a peripheral depending edge portion which is adapted toconfiningly receive a spring assembly within the bounds thereof tofacilitate inter connection of the foam pad and spring assembly, andprevent lateral shifting therebetween.

It is also an object of the present invention to provide an inner springmattress comprising a pair of opposing foam pads of the aboveconstruction with a spring assembly positioned therebetween.

It is still another object of the present invention to provide a methodof forming a foam pad which includes foaming a foamable material in anopen top mold. and wherein a major portion of the upper surface may beleveled during the foaming operation to thereby provide a relativelyflat area for contacting an adjacent spring assembly.

It is a further object of the present invention to provide a method offorming a foam pad in an open top mold and wherein the upper surface isleveled during the foaming operation without significantly interferingwith the formation of a dense upper crust.

It is also an object of the present invention to provide a method offorming a foam pad having a raised edge along the periphery of the uppersurface which is adapted to confiningly receive an adjacent springassembly.

These and other objects and advantages of the present invention areachieved in the embodiments of the present invention illustrated hereinby the provision of a spring cushion construction which comprises afoamed pad having a generally flat inner surface and a dependingperipheral edge. (The edge is generally re ferred to herein as raisedwhen described in association with the method of the present invention.and as "depending" \vhen described in association with the product sincethe pad is typically \'ic\\ ed as being inverted when assembled to thespring assembly.) The flat inner surface includes a dense outer crust.and a spring assembly is positioned so that the terminal face portionsthereof contact the outer crust without significantly penetrating thesame so that the crust serves as an insulator to prevent the springassembly from penetrating into the interior of the pad during use. Also.the depending edge confiningly receives the spring assembly within thebounds thereof such that the edge serves to prevent lateral shiftingbetween the spring assembly and pad.

The above cushion construction is fabricated by a method which includesfoaming an elastomcric mate rial in an open top mold so as to form adense upper crust thereon. and leveling the upper surface during thefoaming operation by positioning an opemvork mold insert in floatingrelation thereon. the openwork nature of the insert serving to maintaina substantial portion of the foaming material in Contact with the air tothereby result in the formation of the dense upper crust. A raised foamedge may then be formed by depositing additional foamable material in achannel formed between the mold and mold insert.

Some of the objects of the invention having been stated. other objectswill appear as the description proceeds. when taken in connection withthe accompanying drawings. in which FIG. I is a flow chart illustratingthe steps of a method of making a foam pad and embodying the presentinvention;

FIG. 2 is a schematic illustration of an apparatus adapted to carry outthe method illustrated in FIG. 1;

FIG. 3 is a schematic illustration of the initial step in the methodillustrated in FIG. 1;

FIG. 4 is a schematic illustration of the subsequent step of applyingheat to the surface of the foaming material;

FIG. 5 is a schematic illustration of the subsequent step of positioninga mold insert on the foaming material;

FIG. 6 is a schematic illustration of the subsequent step of forming araised foam edge along the periphery of the foam material by positioningadditional foamable material in the channel formed between the moldinsert and mold;

FIG. 7 is a view similar to FIG. 5. but illustrating an alternateembodiment wherein the mold insert and an open mesh scrim fabric arepositioned on the foaming material;

FIG. 8 is a view similar to FIG. 7, but illustrating another embodimentwherein an open mesh scrim fabric is presecured to the mold insert priorto being positioned on the foaming material;

FIG. 9 is a sectioned perspective view illustrating the mold. moldinsert. and resulting pad as seen in FIG. 6;

FIG. 10 is a sectioned perspective view illustrating another embodimentwherein the upstanding flange of the mold insert comprises a relativelyfine. openwork screen;

FIG. 11 is a sectioned perspective view illustrating the embodimentshown in FIG. 8 and wherein the open mesh scrim fabric is presccured tothe mold insert;

FIG. 2 is a sectioned perspective view illustrating another embodimentwherein the upstanding flange of the mold insert includes a laterallydirected peripheral rib for forming a channel along the inwardly facingsurface of the raised edge;

FIG. I3 is a schematic illustration of an alternate method for forming araised edge along the periphery of the foam pad by positioning a stripof foamed material in the channel formed between the mold and moldinsert;

FIG. l4 schematically illustrates another embodiment of a method forforming a raised edge and wherein a strip of foamed material is securedto the pad after removal from the mold;

FIG. 15 is a pcrspectivc view. partly broken away. illustrating a foampad embodying the features of the present invention;

FIG. 16 is a sectioned perspective view of the pad illustratcd in FIG.15'.

FIG. 17 is a sectioned perspective view similar to FIG. I6. butillustrating an embodiment resulting from the use of a mold insert asshown in FIG. 10 and wherein a crust is formed on the inwardly facingsurface of the raised foam edge;

FIG. 18 is a sectioned perspective view similar to FIGv 16. butillustrating another embodiment resulting from the use of a mold insertas shown in FIG. 8 and wherein a reinforcing open mesh scrim fabric isembedded in the crust of the flat central portion of the pad and theinwardly facing surface of the raised foam edge;

FIG. 19 is also a view similar to FIG. 16 but illustrating a foam padresulting from the use of a mold insert as shown in FIG. l2;

FIG. 20 is a sectioned perspective view ofa foam pad resulting from themethod illustrated in FIG. 13;

FIG. 21 is a perspective view. partly broken away. of an inner springfoam mattress which embodies the present invention;

FIG. 22 is a fragmentary sectional view of an inner spring foam mattresswhich embodies the present invention'.

FIG. 23 is a view similar to FIG. 22 wherein the pads of the mattressinclude a peripheral channel adapted to receive the border wire of thespring assembly;

FIG. 24 is a view similar to FIG. 22 but illustrating the embodimentwherein the raised edge is separately formed from the remainder of thepad and attached as shown in FIGS. 13 or 14;

FIG. 25 is a perspective view. partly broken away. of a seat cushionwhich embodies the present invention;

FIG. 26 is a fragmentary sectional view of a seat cushion which embodiesthe present invention;

FIG. 27 is a view similar to FIG. 26 and illustrating the embodimentwherein the foam pad includes 21 peripheral channel for receiving theborder wire of the spring assembly;

FIG. 28 is a view similar to FIG. 26 and illustrating the embodimentwherein the raised edge is separately formed from the remainder of thepad; and

FIG. 29 is a fragmentary perspective view of an inverted foam pad andspring assembly of the construction illustrated in FIG. 27.

Referring more specifically to the drawings. FIGS. I and 2 schematicallyillustrate a process and apparatus for fabricating a foam pad adaptedfor use in an inner spring mattress 30 as shown in FIG. 2]. or in a seatcushion 32 as shown in FIG. 25. According to the illustrated embodiment.the method is carried out on an apparatus which comprises an endlesshorizontal trackway 34 of conventional construction and which is adaptedto convey a number of open top molds 36 thcrcabout. More particularly.the trackway 34 sequentially conveys cach open top mold 36 past a moldfilling station 38, a hcating station 39, an insert assembly station 40.an edge forming station 41. an insert removal station 42. and a padremoval station 43.

Viewing first the mold filling station 38 as seen in FIGS. 2 and 3. apredetermined quantity of a foam-able material 46 is fed from a suitablesource of supply 47 and sprayed or otherwise deposited in the open topmold 36 through a number of nozzles 48 or the like. The mold 36 istypically constructed from a lightweight material such as aluminum. andcomprises a generally flat bottom wall 50 and a raised peripheral edgewall SI which defines a generally rectangular peripheral outline.

After the foamable material 46 is received in the mold. the evolution ofcarbon dioxide or other blowing agent causes the material to expand andrise within the mold to form a foamed cellular elastomeric pad 54 (FIG.15) as hereinafter further described. In addition. it is acharacteristic of the ingredients of the foamable material employed withthe present invention that tough dense outer crust 55 (best seen in FIG.I6) is formed along the upper surface of the pad during the foamingprocess. The exact reasons for the formation of this crust are not fullyunderstood. but it is believed that the formation is dependent uponcontact with the atmosphere since a crust of this type is not formedalong the bottom and side walls of the pad which are in contact with themold surfaces. Typically. the crust has a thickness of about 1/16 inch.although in accordance with the present invention. the thickness may besubstantially increased. More particularly. the thickness of the crustmay be increased to a thickness substantially greater than 1/16 inch,such as about 1/8 inch, by heating the upper surface of the foamingmaterial with infrared lamps 57 at the heating station 39.

As noted above, it is a characteristic of the described foamablematerial to form a rounded or crowned upper surface during the foamingoperation. In accordance with the present invention, at least a majorportion of the upper surface is leveled during the foaming operation todefine a substantially level central portion 58 in the resulting pad 54,and this leveling operation is performed while maintaining a substantialportion of the central portion 58 in contact with the surrounding air tothereby result in the dense upper crust 55 being formed thereon. Theabove functions are achieved in the illustrated embodiment by the use ofan openwork mold insert 60 which is positioned on the upper surface ofthe foaming material 46 so as to be floatingly carried thereon.

The insert 60 is typically fabricated from a suitable metallic materialsuch as aluminum and comprises a generally flat openwork member 62 andan upstanding imperforate flange 63 surrounding the member. The flange63 thereby defines a peripheral border extending above the plane of themember 62, and the border generally conforms to the rectangularperipheral outline of the mold 36 such that the mold insert is adaptedto be positioned within the mold and spaced a substantially uniformdistance from the peripheral edge wall 51 of the mold to thereby definea relatively narrow, open channel 64 therebetween.

The member 62 may be composed of a screen of uniform construction formedin any suitable manner. such as by interlacing strands of material suchas metal wire. Alternately. the screen could take the form of a conventionally formed expanded metal member. By design, the member 62 iscomposed primarily of open area, e.g., at least about 75%, to permit airto reach a substantial portion of the underlying upper surface andthereby permit the formation of crust 55 thereon. As shown, the member62 comprises a screen formed of woven wire fabric (note FIG. 9), andtypically the wires of the fabric have a diameter of about 1/16 inch andthe openings are between about to V2 inch square. Thus the wires of thescreen overlie a relatively small part of the area of the centralportion, and the development of the crust 55 is not significantlyretarded by the presence of the mold insert.

As seen for example in FIGS. 5, 6 and 9, the mold insert includes anumber of areuately curved handles 65 carried along the flange 63. Moreparticularly. the handles 65 are of a generally inverted U-shapedconfiguration, with the inner leg 65a being attached to the inwardlyfacing edge of the flange 63, and the outer leg 65b serving as a cam forengaging the outer edge of the wall 51 of the mold. By this arrangement,the insert may be conveniently lifted by the workmen, and guidinglycentered within the peripheral outline of the mold such that the moldinsert is free to rise upwardly with the foaming material while beingmaintained in its cen tralized location with respect to the mold.Further, a number of weights 66 in the form of cylindrical washers areadapted to be selectively positioned on the insert 60 by threading thesame onto the handles in a manner apparent from FIGS. 5 and 9. Thus theweight of the insert may be varied to control the height and density ofthe resulting pad. and under certain conditions it is possible that theinsert will remain substantially at its initial elevation and willprevent the rising of the foam.

It is a further aspect of the present invention to form a raised foamedge 67 along the periphery of the upper surface of the pad. the raisededge being designed to confiningly receive a spring assembly within thebounds thereof in a manner further described below. As illustrated inFIG. 6, additional foamable material 68 may be deposited in the openchannel 64 between the edge wall 51 of the mold and the flange 63 of themold insert to form the raised edge 67. By this arrangement, theadditional foamable material 68 rises within the channel 64 andself-adheres to the upper surface of the underlying material 46 to formthe raised edge 67.

The additional foamable material 68 may be deposited by an arrangementwhich includes a supply source 70, and a movable nozzle 71 operativelyconnected to the supply source. The nozzle 71 may be movable by hand, ora mechanism of suitable design (not shown) may be provided forautomatically translating the nozzle 71 along the channel 64. Also.while it is generally preferred to add the additional foamable materialimmediately after positioning of the mold insert on the underlyingmaterial 46, it should be understood that this step may be conductedafter the foaming operation of the underlying material 46 issubstantially completed since the additional material 68 readilyself-adheres to the crust which would be formed on the underlyingmaterial, Also, as seen for example in H05, 9 and 16. a crust 72 isformed along the upper surface of the edge 67. While the additionalfoamable material 68 is typi cally ofa composition similar to that ofthe initial material 46, the additional material may. if desired, beselected to produce a somewhat higher density foam and thus provideincreased rigidity and resistance to penetration by the spring assembly.

When the foaming process for both the underlying material 46 andadditional material 68 is substantially completed. the mold insert isremoved from the resulting pad 54 at station 42. The pad 54 is thenstripped from the mold at station 43. ln this regard. it will be understood that the mold insert 60 may be coated with a conventionalrelease agent. such as wax. Teflon or sili cone to prevent adherence tothe crust 55, and the mold 36 may be similarly coated to facilitateremoval of the pad therefrom. Also. it will be understood that the padand mold insert could be initially removed from the mold as a unit. andthe pad then stripped from the insert.

As best seen in FIGS. 15l6, the resulting pad 54 comprises a generallyflat bottom or outer surface 74. and an inner surface comprising thegenerally flat central portion 58 and the raised edge 67. The centralportion 58 will be seen to have a gridwork of indentations thereinresulting from the wires of the screen 62 of the mold insert. The pad 54is thus in a form which may be conveniently shipped or stored prior tobeing interconnected with a spring assembly, or alternatively, the padmay be immediately joined to the spring assembly.

Where the pad 54 is to be employed in the fabrication of an inner springmattress 30 as seen in FIGS. 2l-24, a spring assembly 76 is disposedintermediate two substantially identical pads 54a, 54b. the pad 540being inverted so that they are disposed in an adjacent. parallelrelationship with the inner surfaces facing each other. The springassembly 76 itself is generally conventional. and includes generallyflat upper and lower terminal face portions 77, 78, respectively. witheach face portion Contacting the central portion of the associated padsuch that the outer crust serves as an insulator to prevent the terminalface portions from penetrating into the interior of the pads during use.Also. each face of the spring assembly includes a relatively heavyperipheral border wire 79 having a smaller helical wire 80 disposedthereabout. The spring assembly has an overall configuration generallyconforming to that of the central portion of each pad such that it isconfiningly received within the bounds of the depending edges 67a, 67bof the pads whereby the depending edges serve to prevent lateralshifting between the spring assembly and pads. To maintain the springassembly in assembled relation with the pads, there is further provideda fabric covering 82 in the form of a mattress ticking which completelysurrounds the assembled spring assembly and pads. Also, it will be notedthat the edges 67a, 67b of the pads substantially contact each other toprovide additional firmness along the periphery of the mattress where auser commonly sits.

The pad 54 of the present invention is also adapted for use in thefabrication of a seat cushion 32 as shown in FIGS. 25-28. As illustratedin FIG. 26, a single pad 540 is joined to one side of a spring assembly76 such that the terminal face portions 77 of the spring assemblycontact the outer crust of the pad 541' in the manner described above.Here again, the spring assembly 76 has an overall configuration so as tobe confiningly received within the bounds of the depending foam edge 67cso as to prevent lateral shifting between the spring assembly and pad.To maintain the spring assembly and pad in assembled relation. a fabriccovering 84 (FIG. 25) may be employed to join the same to the frame ofthe seat. or a suitable adhesive may be used.

In the embodiment of the invention illustrated in FIG. 7, an open meshfabric 90 or scrim is initially positioned on the foaming material 46 soas to be floatingly carried thereon and underlie the mold insert 60. Bythis arrangement. the mesh fabric 90 becomes essentially embedded in theupper crust to thereby reinforce the same. The fabric 90 is generallyconventional, and may for example comprise four by four cottom meshfabric (defined as having four openings per inch in each of the twotransverse directions), or five by five cotton mesh fabric.

In order to facilitate the placement of the mesh fabric 90 on thefoaming material 46, the fabric may be presccured to the lower surfaceof the mold insert 60 such that the fabric and insert are positioned onthe foaming material substantially concurrently, note FIGS. 8 and 11. Inthis embodiment, a plurality of spaced pins 92 are positioned along theinwardly facing surface of the flange 63 of the insert so that thefabric 90 may be drawn over the top of the flange and secured to thepins in the manner best seen in FIG. 11. When the foaming of thematerial is completed. the fabric is released from the pins 62, and theinsert removed. This results in the pad as shown in FIG. 18 wherein themesh fabric is cmbcdded in the crust 55 along the central portion. andalong the inwardly facing surfacc of the raised edge 67. In thisarrangement. the fabric 90 not only reinforces the crust, but alsoserves to prevent the spring assembly from cutting laterally into theraised edge of the pad Another embodiment ot'thc present invention isillustratcd in FIGS. 10 and 17 wherein the flange of the mold insertcomprises a relatively fine. opcnwork screen 94 supported by a frameworkof interconnected rods 95. The screen 94 is adapted to permit air topass thcrethrough and contact the inside surface of the foamablematerial deposited in the open channel, to thereby permit the formationof a dense crust 96 on the inwardly facing surface of the resultingraised edge. In this regard, the fineness of the screen 94 should becorrelated to the viscosity of the foamable material deposited in theopen channel such that the foamable material will not penetrate thescreen. For typical foamable materials, the screen should be of afineness comparable to ordinary household window screening. FIGS. 10 and17 further illustrate the above described condition wherein the foamablematerial 68 added to form the raised edge produces a higher density foamthan the initial foamable material 46.

As seen in the embodiment illustrated in FIG. 12, the mold insertincludes a laterally directed peripheral rib 98 which extends along thelower edge of the flange 63 and into the channel 64. The rib thus liessubstantially coplanar with the screen 62, and is adapted to form aperipheral channel 99 along the base of the inwardly facing surface ofthe raised foam edge as seen in FIG. I9. As will become apparent, thechannel 99 is adapted to receive the wires 79 and 80 of the springassembly 76, such that the channel acts to retain the wires therein andthereby interconnect the pad and spring assembly. This arrangement isspecifically shown in the inner spring mattress illustrated in FIG. 23,and the seat cushion illustrated in FIG. 27.

An alternate arrangement for forming the raised edge 67 along theperiphery of the upper surface of the pad is illustrated in FIG. 13. Inthis embodiment, a cut strip I02 of foamed material is applied along theperiphery of the material 46, with the channel 64 serving to guide thepositioning of the strip thereon. The strip may be so positioned whilethe foaming operation is proceeding, in which case the tacky nature ofthe foaming material will self-adhere the strip thereto. Alternately,the strip may bejoined thereto by means of a suitable adhesive after thefoaming operation is completed. As seen in FIG. 20. the strip 102 mayinclude a dense outer crust I03 along the inside surface thereof toserve as an insulator against the lateral movement of the springassembly. The embodiment shown in FIG. 14 is generally similar to thatdescribed above, with the exception that a strip 104 of foamed materialis applied along the periphery of the pad subsequent to the removal ofthe in sert. In this case, a flame as shown schematically at 106 may beemployed to melt the surface of the foam to permit self-adherence of thestrip to the pad. or a suitable adhesive could be employed for thispurpose. FIG. 24 illustrates an inner spring mattress formed by thisprocedure. whilc FIG. 28 illustrates a similarly formed seat cushion.

Foam pads produced in accordance with the present invention typicallymeasure about ll": to 2 inches in thickness at the center portion 58,and the edges 67 are about 2 to 3 inches in height and about 1 to 2inches in width. Also. the flanges 63 of the insert may be slightlytapered as shown in the drawings to facilitate removal thcrcol' from thepad, thus resulting in a slightl tapered inwardly facing surface on theedge.

As noted aho\e. the weight of the insert 60 may be vnricd by means ofthcremovable weights 66 to control the height and density of the underlyingfoam. In this rcgurd. it will he understood that the weight of theinsert serves to retard expansion and densify the foam therebeneath.while permitting the free expansion of the foam along the border withinthe channel 64. This free expansion may under certain conditions resultin the formation of a raised edge of significant height, therebyeliminating or at least reducing the required amount of the additionalfoamable material 68.

The specific ingredients of the foaming material employed with thepresent invention are generally conventional. and may comprise a varietyof well-known resin foaming compositions which are adapted to expand andcure in situ as it is poured into the mold and which is self-curing atroom temperature and thus does not require any after treatment such asheating. A foam which meets the above requirements and which alsoproduces a dense outer crust as described above is chemically blownurethane foam.

A specific nonlimiting example of a suitable urethane foaming materialis set forth below:

Niax Polyol l [-34 is a 5000 molecular weight polyether triol cappedwith ethylene oxide to give a very high primary hydroxyl content. NiaxPolyol 34-28 is a polymer polyol. made by insitu polymerization of avinyl containing monomer in a conventional polyol. Niax Catalyst A-] isa 70% solution of bis (2- dimethylaminoethyl) ether in dipropyleneglycol. Niax Catalyst NEM is N-ethyl morpholine. Solid DABCO is apowdered cyclic triethylene diamine. Niax lsocyanatc TDI is toluenedi-isocyanate. Niax lsocyanate AFPl is methylene bis-phenyl isocyanate.The resulting foam is relatively hard, and has a core density of about2.48 pounds per cubic foot.

Foam pads produced in accordance with the above formulation can normallybe demolded approximately 5 to 8 minutes after the mold fillingoperation. The following is a specific non-limiting example of a typicaltiming sequence for the various operation of the present invention:

a. The initial foamable material 46 is deposited in the mold 36.

b. Heat from the infrared lamps 57 is applied to the surface of thefoaming material approximately l /2 minutes after the material has beendeposited in the mold, and the heat is applied for approximately 1minute to develop a thick crust.

c. After the heating operation is terminated. the insert 60 is appliedand maintained on the rising foam material for approximately 2 /2minutes.

d. The additional foamable material 68 is deposited in the channel 64during the foaming of the initial material such that the foaming of theinitial material and the additional material 68 occurs substantiallyconcurrently.

e. Upon completion of foaming, the insert is removed, and after a shortadditional cooling period. the pad 54 may be stripped from the mold.

Further details relating to the apparatus employed in the practice ofthe present invention may be obtained from applicant's copendingapplication entitled Apparatus For Fabricating Foam Pads". Ser. No.478,617. and filed concurrently herewith.

In the drawings and specification, there has been set forth a preferredembodiment of the invention. and although specific terms are employed,they are used in a generic and descriptive sense only and not forpurposes of limitation.

That which is claimed is:

1. A spring cushion construction for use as a seat, mattress or the likeand comprising a foamed cellular elastomeric pad comprising a generallyflat outer surface, and an inner surface including a generally flatcentral portion and a depending edge extending about at least asubstantial portion of the periphery of said central portion, saidcentral portion of said inner surface including a dense outer crust ofsubstantial toughness.

a spring assembly disposed immediately below said central portion ofsaid inner surface and including a terminal face portion contacting saidouter crust to thereby support said elastomeric pad and with said outercrust serving as an insulator to prevent said terminal face portion frompenetrating into the interior of said elastomeric pad during use. saidspring assembly having an overall configuration generally conforming tothat of said central portion so as to be confiningly received within thebounds of said depending edge and wherein said edge serves to preventlateral shifting between said spring assembly and pad. and

means for maintaining said spring assembly in assembled relation withsaid elastomcric pad to prevent the separation thereof.

2. The spring cushion construction as defined in claim 1 wherein saiddepending edge is integral with the remainder of said elastomcric pad.

3. The spring cushion construction as defined in claim 1 wherein saiddepending edge is separately formed from the remainder of saidelastomcric pad and is secured thereto.

4. The spring cushion construction as defined in claim 1 wherein saiddepending edge defines an inwardly facing surface. said surfaceincluding a dense outer crust.

5. The spring cushion construction as defined in claim 1 wherein saiddense outer crust has a thickness greater than about 1/16 inch.

6. The spring cushion construction as defined in claim 1 wherein thedensity of the foam of said depending edge is substantially higher thanthe density of the foam of said central portion.

7. The spring cushion construction as defined in claim 1 furthercomprising an open mesh fabric essentially embedded and thereby securedin said outer crust to reinforce the same.

8. The spring cushion construction as defined in claim 1 wherein saiddepending edge defines an inwardly facing surface, and furthercomprising an open mesh fabric essentially embedded in said outer crustof said central portion and in said inwardl facing surface of said edgeportion.

9. The spring cushion construction as defined in claim 1 wherein saidmeans for maintaining said spring assembly in assembled relation withsaid pad comprises a fabric overlying said outer surface of said pad andsubstantially surrounding said spring assembly.

10. The spring cushion construction as defined in claim I wherein saidterminal face portion of said spring assembly includes a relativelyrigid wire extending about the periphery thereof. and wherein said meansfor maintaining said spring assembly in assembled relation with said padincludes a peripheral channel formed in said pad along the intersectionof said central portion and depending edge, said rigid wire beingreceived within said channel such that said channel acts to retain saidwire therein.

ll. The spring cushion construction as defined in claim 10 wherein saidterminal face portion of said spring assembly further includes a helicalwire disposed about said rigid wire such that both said helical wire andrigid wire are received within said channel.

l2. An inner spring foam mattress comprising first and second foamedcellular elastomeric pads,

each of said pads comprising a generally flat outer surface and an innersurface including a generally flat central portion and a depending edgeextending about the periphery of said central portion. at least saidcentral portion of each pad including a dense outer crust, and said padsbeing disposed in an adjacent. parallel relationship with said innersurfaces and depending edges facing each other.

a spring assembly disposed intermediate said pads and includinggenerally flat upper and lower terminal face portions contactingrespective central portions of said pads such that said outer crustserves as an insulator to prevent the terminal face portions frompenetrating into the interior of the elastomeric pad during use, saidspring assembly having an overall configuration generally conforming tothat of said central portion of each pad so as to be confininglyreceived within the bounds of said depending edge of each pad such thatsaid edges serve to prevent lateral shifting between said springassembly and pads, and

means for maintaining said spring assembly in assembled relation withsaid elastomeric pads to prevent the separation thereof.

13. The inner spring foam mattress as defined in claim 12 wherein saidmeans for maintaining said spring assembly in assembled relation withsaid pads comprises a fabric completely surrounding the assembled springassembly and pads.

14. The inner spring foam mattress as defined in claim 13 wherein saiddense outer crust of each pad has a thickness greater than about l/l6inch.

15. The inner spring foam mattress as defined in claim l3 furthercomprising an open mesh fabric essentially embedded in said outer crustof said central portion of at least one of said pads to therebyreinforce the crust

1. A spring cushion construction for use as a seat, mattress or the likeand comprising a foamed cellular elastomeric pad comprising a generallyflat outer surface, and an inner surface including a generally flatcentral portion and a depending edge extending about at least asubstantial portion of the periphery of said central portion, saidcentral portion of said inner surface including a dense outer crust ofsubstantial toughness, a spring assembly disposed immediately below saidcentral portion of said inner surface and including a terminal faceportion contacting said outer crust to thereby support said elastomericpad and with said outer crust serving as an insulator to prevent saidterminal face portion from penetrating into the interior of saidelastomeric pad during use, said spring assembly having an overallconfiguration generally conforming to that of said central portion so asto be confiningly received within the bounds of said depending edge andwherein said edge serves to prevent lateral shifting between said springassembly and pad, and means for maintaining said spring assembly inassembled relation with said elastomeric pad to prevent the separationthereof.
 2. The spring cushion construction as defined in claim 1wherein said depending edge is integral with the remainder of saidelastomeric pad.
 3. The spring cushion construction as defined in claim1 wherein said depending edge is separately formed from the remainder ofsaid elastomeric pad and is secured thereto.
 4. The spring cushionconstruction as defined in claim 1 wherein said depending edge definesan inwardly facing surface, said surface including a dense outer crust.5. The spring cushion construction as defined in claim 1 wherein saiddense outer crust has a thickness greater than about 1/16 inch.
 6. Thespring cushion construction as defined in claim 1 wherein the density ofthe foam of said depending edge is substantially higher than the densityof the foam of said central portion.
 7. The spring cushion constructionas defined in claim 1 further comprising an open mesh fabric essentiallyembedded and thereby secured in said outer crust to reinforce the same.8. The spring cushion construction as defined in claim 1 wherein saiddepending edge defines an inwardly facing surface, and furthercomprising an open mesh fabric essentially embedded in said outer crustof said central portion and in said inwardly facing surface of said edgeportion.
 9. The spring cushion construction as defined in claim 1wherein said means for maintaining said spring assembly in assembledrelation with said pad comprises a fabric overlying said outer surfaceof said pad and substantially surrounding said spring assembly.
 10. Thespring cushion construction as defined in claim 1 wherein said terminalface portion of said spring assembly incLudes a relatively rigid wireextending about the periphery thereof, and wherein said means formaintaining said spring assembly in assembled relation with said padincludes a peripheral channel formed in said pad along the intersectionof said central portion and depending edge, said rigid wire beingreceived within said channel such that said channel acts to retain saidwire therein.
 11. The spring cushion construction as defined in claim 10wherein said terminal face portion of said spring assembly furtherincludes a helical wire disposed about said rigid wire such that bothsaid helical wire and rigid wire are received within said channel. 12.An inner spring foam mattress comprising first and second foamedcellular elastomeric pads, each of said pads comprising a generally flatouter surface, and an inner surface including a generally flat centralportion and a depending edge extending about the periphery of saidcentral portion, at least said central portion of each pad including adense outer crust, and said pads being disposed in an adjacent, parallelrelationship with said inner surfaces and depending edges facing eachother, a spring assembly disposed intermediate said pads and includinggenerally flat upper and lower terminal face portions contactingrespective central portions of said pads such that said outer crustserves as an insulator to prevent the terminal face portions frompenetrating into the interior of the elastomeric pad during use, saidspring assembly having an overall configuration generally conforming tothat of said central portion of each pad so as to be confininglyreceived within the bounds of said depending edge of each pad such thatsaid edges serve to prevent lateral shifting between said springassembly and pads, and means for maintaining said spring assembly inassembled relation with said elastomeric pads to prevent the separationthereof.
 13. The inner spring foam mattress as defined in claim 12wherein said means for maintaining said spring assembly in assembledrelation with said pads comprises a fabric completely surrounding theassembled spring assembly and pads.
 14. The inner spring foam mattressas defined in claim 13 wherein said dense outer crust of each pad has athickness greater than about 1/16 inch.
 15. The inner spring foammattress as defined in claim 13 further comprising an open mesh fabricessentially embedded in said outer crust of said central portion of atleast one of said pads to thereby reinforce the crust.